The desirability of adding a fragrance to laundry during the cleaning process has been recognized for decades. A vast array of scented fabric conditioners are available on the market today. These products combine perfumes with softening and conditioning agents to produce laundry that is soft, fresh smelling, static-free, crease-resistant, and easily ironed. In one approach, the conditioners are added during the wash cycle in a washing machine. However, this approach may be wasteful, because much of the perfumes on conditioners in the conditioning compositions do not adhere to the clothes in a washer and are washed away with the waste water. To avoid this waste, many consumers now add fabric conditioners during the drying process in a dryer. As discussed below, this approach has not been entirely satisfactory in imparting a lasting fragrance to freshly laundered articles.
Various methods for adding a fragrance to laundry in a dryer are well known. One of the most common methods employs dryer sheets which are impregnated with conditioning agents and allowed to tumble with the clothes in a dryer. During the drying process, fragrance is imparted to the clothes that come into contact with these dryer sheets. The dryer sheets are typically made of a spongy material and the conditioning agents are chosen such that they melt or flow at conventional dryer operating temperatures. Unfortunately, these dryer sheets suffer from several drawbacks. First, because the conditioning agents are applied by contact between articles of laundry and the sheets, application can be splotchy and uneven. In addition, in order to assure that all articles of laundry come into contact with the sheet, it is necessary for the dryer sheets to be put in the laundry early on in the drying cycle. This can be disadvantageous because any fragrances in the conditioning compositions are likely to volatilize during prolonged exposure to the heat of the drying cycle, leaving little residual fragrance at the end of the drying process. This problem is worsened in industrial dryers, such as those used by the hotel industry, which operate at much higher temperatures than do conventional home dryers. In fact, many industrial dryers work at temperatures hot enough to melt dryer sheets. Finally, the conditioning agents that can be used with dryer sheets are limited because they must be selected from compounds that melt or flow in a fairly specific temperature range. The compositions that meet these criteria are not optimally suited for use as softeners and conditioners.
In other laundry softening or conditioning methods, liquid or powder conditioners are housed in porous containers which are either allowed to tumble freely with the laundry in a dryer or which are attached to the drum of the dryer such that they spin with the laundry. These liquid or powder conditioners are then dispensed through the porous walls of the container during the drying process. As with dryer sheets, these porous containers apply conditioning agents by making direct contact with articles of laundry, which requires prolonged exposure to the laundry during the drying cycle and which may lead to an uneven application of the conditioning agents.
In another method, a fabric softener or conditioner is held in a container within a dryer and hot air is circulated over the container such that the fabric softener or conditioner vaporizes and is carried by the air stream over the laundry. This requires that the softener or conditioner be present during the hottest part of the drying cycle, resulting in the volatilization and loss of volatile fragrant components within the conditioning compositions.
Finally, it is known to spray or sprinkle liquid softeners or conditioners onto either the damp clothes as they enter the dryer, or onto the drum itself before the clothes are placed in the dryer such that the softener or conditioner permeates the laundry as it dries. Unfortunately, the spray nozzles used to apply conditioning compositions frequently dispense the liquids in droplets, rather than a fine mist or vapor which makes it difficult to precisely control the amount and distribution of the liquids as they are applied to laundry.
None of these methods has been entirely successful at imparting a lasting residual fragrance to articles of laundry. Thus, a need exists for a system that is able to impart a fragrance to laundry in a dryer without substantial loss of the fragrance before the completion of the drying process. Such a system would be of particular value to the hotel industry, where fresh-smelling robes, towels, and linens would enhance the comfort of guests and potentially create more repeat customers.